Abstract: A propulsion system made up of an engine located in the interior of a marine vessel is provided. The engine has an exhaust discharge member in communication with a propulsion unit. A gimbal ring has a pivotable exhaust passage connected to pass exhaust from the discharge member to the propulsion unit.

Abstract: A propulsion system for a watercraft is provided, which may be an integral part of a watercraft or may be retrofitted to a particular watercraft. The propulsion system is fixedly mounted to the hull in a central area, rather than along the perimeter of the watercraft. The propulsion system includes a jet-drive assembly coupled to a jet, an angular drive assembly for rotating the jet, and a control system for controlling the jet-drive assembly and the angular drive assembly.

Abstract: A propulsion system for a watercraft is provided, which may be an integral part of a watercraft or may be retrofitted to a particular watercraft. The propulsion system is mounted to the hull in a central area, such as forward of a transverse centerline of the hull. The propulsion system includes a propulsion assembly coupled to a retractable arm, which is pivotable between a stowed and operational position. In the stowed position at least a portion of the propulsion assembly may be received within a recessional housing formed in the hull.

Abstract: A water jet apparatus with counter-rotating impellers for propelling a boat. The impellers are coupled by an assembly comprising an impeller shaft secured to a first impeller and a gear train coupling the impeller shaft to a second impeller for counter-rotation. Preferably the gear train comprises one beveled gear secured to the impeller shaft, another beveled gear secured to the second impeller, and a beveled pinion meshed with the first and second beveled gears. The counter-rotating impellers can be driven by a drive shaft coupled to the first impeller for boats having an inboard motor or by a drive shaft coupled to the pinion for boats having an outboard motor.

Abstract: A pump jet having a perforated wear liner inside the rotor housing for altering the spectrum of noise produced by the pump jet. The perforated wear liner is inserted in a circumferential recess formed on the inner surface of the rotor housing and surrounds the rotor tip region. The throughholes or perforations are preferably constant in size and regularly spaced. The perforated wear liner acts as a Helmholtz resonator liner which alters the spectrum of noise emitted from the pump jet during operation. Proper selection of the size, number and spacing of the holes permits the designer to control the specific noise spectrum range that is emitted from the front and rear lobes of the pump jet, thereby altering the hydrodynamic noise field.

Abstract: A boat or other water craft having an inboard engine, an outboard pump jet apparatus and a transom plate on which the pump jet apparatus is pivotably mounted. The boat hull bottom has a water tunnel formed therein, the transom plate has a tube portion in flow communication with the water tunnel, and the pump jet apparatus has an inlet which, in the operating position of the pump jet, is in flow communication with the tube portion of the transom plate. The pump jet apparatus is selectively pivotable between an operating position and a service position. In the service position the pump jet inlet is accessible to a boat occupant to clear debris from the pump jet inlet.

Abstract: A water jet apparatus mounted to a horizontal hull section and having a shift and steering control assembly which penetrates a hole in that hull section. The shift and steering control assembly has a modular lever and shaft subassembly which is installed in the inlet housing, before the inlet housing is installed in the hull. The modular lever and shaft assembly includes a shift and steering control housing mounted to the inlet housing and having respective bores for housing shift and steering shafts. Upper shift and steering levers are coupled to the upper ends of the shift and steering shafts respectively, while lower shift and steering levers are coupled to the lower ends of the shift and steering shafts respectively. Respective control cables are attached to the upper levers inside the hull; respective control rods for operating a steering nozzle and a reverse gate are attached to the lower levers outside the hull.

Abstract: An arrangement for mounting a water jet apparatus to a hull of a marine craft. The hull has generallly horizontal and vertical sections and sidewalls which define a cavity in which an inlet housing of the water jet apparatus is installed. The inlet housing has a top section which abuts an exterior surface of the horizontal hull section and a front section which abuts an exterior surface of the vertical hull section. A top mounting plate abuts an interior surface of the horizontal hull section, while a front plate abuts an interior surface of the vertical hull section. One set of fasteners hold the top mounting plate, the horizontal hull section and the top section of the inlet housing together. Another set of fasteners hold the front plate, the vertical hull section and the front section of the inlet housing together.

Abstract: A water jet apparatus having a mechanism for providing additional lateral thrust when a boat is moving in reverse. A steering nozzle is pivotably mounted at and in flow communication with the outlet of a flow-through housing, and has a pair of opposing side thrust nozzles. The water flow exiting the steering nozzle is reversed by a reverse gate which covers the main outlet of the steering nozzle and by a reverse nozzle incorporated as part of the steering nozzle. The reversed flow exits the steering nozzle via the reverse nozzle, which directs the reversed flow forward and downward. When the steering nozzle is turned a predetermined angle to one side in reverse, the side thrust nozzle on the opposing side is swung into the path of water flow exiting the housing outlet.

Abstract: A marine craft has with an inlet ramp, which increases in height as the inlet ramp extends rearward, and a cavity which communicates at its front with the rear of the inlet ramp. The cavity is open at its bottom and its rear. The marine craft is propelled by a jet pump apparatus having an inlet housing which is installed in the aforementioned hull cavity. The inlet housing defines an inlet volume in flow communication with the inlet ramp and a water tunnel in flow communication with the inlet volume. The inlet volume has a height which increases as it extends rearward. The inlet ramp and the inlet housing each have a lower U-shaped boundary, which boundaries are connected to form a generally rectangular inlet for water being sucked in by the water jet.

Abstract: A pump jet in which the axial flow of water through the device is controlled by bleeding exhaust gas into the pump jet water stream, thereby producing a thrust loss. The addition of gas into the primary pump jet water flow stream reduces the effective flow density of the exit media, thereby reducing the exit momentum (and thrust) produced by the pump jet. The thrust modulation device can be actuated using any conventional electrical or mechanical actuation subsystem via a knob or lever positioned near the throttle control.

Abstract: A water jet apparatus has a reverse gate which allows a boat or other marine craft to be steered in reverse in the same manner as an automobile. The reverse gate accomplishes this by reversing the flow exiting the steering nozzle. When the steering nozzle is positioned to the left, causing the rearward exit flow to be directed to the left side of a midplane of the water jet apparatus, the reverse gate redirects that leftward and rearward flow so that it flows rightward and forward. Conversely, when the steering nozzle is positioned to the right, causing the rearward exit flow to be directed to the right side of the midplane, the reverse gate redirects that rightward and rearward flow so that it flows leftward and forward.

Abstract: A mount assembly for a trolling motor is provided. The mount assembly includes a bracket adapted to support the trolling motor. A pivoting member, such as a link or an arm, has a first end pivotally coupled to the bracket. The pivoting member is also pivotally coupled to an abutment adjacent a boat deck or gunwale at its second end. A support member is rigidly affixed to a surface of the bracket such that the support member sustains the overhung load of the trolling motor while it is in the stowed position on the boat deck or gunwale. The support member is flat and unobtrusive when the motor is in its run position.